Keeping it comfy

“Everybody into the pool!” rings as a time-honored rallying cry. But when it’s time for everyone to get out, the pool ought to be covered — especially if it’s heated.

That’s the advice from the Cooperative Research Network (CRN), the research arm of the National Rural Electric Cooperative Association. CRN and its strategic partner E Source have been looking at ways that homeowners, swim clubs, and other pool operators can reduce heat loss.

About 70 percent of the heat lost from pools — both indoors and outdoors — results from evaporation. “You experience evaporation both from the sun and from the wind,” explains Brian Sloboda, CRN senior program manager. “People tend not to realize that wind causes water evaporation — a lot of it.”

He adds: “You end up replacing lost water with tap water, which is going to be colder. So you have to reheat it, which increases your electric bills.” So, to save energy, cover a heated pool when it’s not in use. If it’s not heated, you’ll keep its water warmer by covering it.

Longer swimming season

By the way, you also extend your swimming season by a month or more by adding a cover, especially in warmer climates. In much of North Carolina, that can mean enjoying your pool until late fall.

Choosing a cover

Of course, pool size and shape factor into choosing the right cover. The most expensive pool covers are incorporated into the pool structure and can come with an automatic retraction and storage system. Manual covers may be cheaper, but removing them can be a dirty job. You can also choose solar covers resembling bubble wrap. All three have liability issues that need to be addressed.

“If you don’t want to use a physical cover, opt for a chemical cover,” Sloboda offers. “You essentially create a layer of fatty oil on top of your pool. When the water is calm the oil floats to the surface to provide a barrier. While swimmers won’t notice it, it’s not 100 percent effective because when people are swimming or if the wind blows hard pool water mixes with the oil.”

CRN and E Source looked at the cost of heating outdoor pools in several U.S. cities and found that it costs $168 to heat a covered pool in Phoenix, for example, over a seven-month season. Without a cover, the price tag skyrockets to $1,776 — more than 10 times higher.